Calipers.



No. 797,409. PATENTED AUG. 15, 1905. P. MD DAVISm UALIPEIWU APPLICATIONFILED 1330.16 1904.

Elm/04441344 I 9% fizz/m PATENT OFFICE.

' ll'FllTFD STATES WALH EW.

Specification of Letters Patent.

Patented. Aug. 15, 1905.

Application filed December 16, 1904. fierial No. 237,101.

To all. 1071,0122, it may concern.-

Be it known that l, FRANK. M. DAVIS, residmg in Mllwaukee, 1n the countyof Milwaukee and State of Wisconsin, have invented new and usefulImprovements in Calipers, of which the following is a description,reference being had to the accompanying drawings, which are a part ofthis specification.

Calipers in various forms are in small sizes employed very widely formeasuring small articles having convex or concave faces and havingmicrometers on or with them are capable of determining and indicatingvariations in measurement of a fraction of a thousandth of an inch, andnot only are small articles thus measured, but in the mechanic arts ofthe present day it has become necessary to measure with exactness, evento the fraction of a thousandth of an inch, large articles such as theinterior of the cylinders of engines of large size, the exterior ofpistons, and of shafts of relatively great diameter. A caliper that islarge enough to be adapted for measuring large articles must be ofcorrespond" ingly large size, and it must be strong and rigid, so as notto be capable of vibration or yielding, and while strong and rigid it isalso important that it be light in weight, so as to be adapted to bereadily and even easily handled by the workman. A workman cannot use alarge caliper Weighing as much as the large calipers now in use do for avery long time before his arm becomes so tired of holding out theimplement that he cannot make careful and exact measurements with it..Not only this, but the heavy calipers in common use are, because oftheir weight, not adapted to respond to or to transmit to the hand ofthe user the initial contact or slight touches of the instrument on thearticle to be measured in such manner as is desirable for obtaining thebest results.

A chief object of my invention is to provide a caliper-frame that isexceedingly strong in its structure, that is absolutely rigid inquality, and that is very light in weight, while it can be produced insimple form at a minimum of expense; also with my improved caliper-framell provide improved means for adjusting and clamping the spindles in thelegs of the frame, whereby a more ready adjustment and secure holding ofthe spindles and their sleeves can be obtained than has heretofore beensecured.

The invention consists of the improved caliper and its combinations, asherein described and claimed, or the equivalents thereof.

Calipers are employed for outside and for inside measurements, and forconvenience of illustration 1 have shown a caliper embodying myimprovements adapted for outside measurements; but it will be understoodthat by reversing the direction of the projection of the spindles thecaliper would be adapted for making inside measurements.

In the drawings, Figure 1 shows my improved caliper. Fig. 2 is a centralvertical section of the caliper shown in Fig. 1 looking toward the left.Fig. 3 is a section at a right angle to the length of the caliper of theconstruction in detail at the left in Fig. 1. Fig. at is a section inthe direction of the length of the caliper of the details ofconstruction at the right in Fig. 1. Fig. 5 represents the blank in theform and as cut from sheet-steel for the manufacture therefrom of theprineipal portion of the frame of my improved caliper. Fig. Grepresentsthat portion of the frame of the caliper made from the blank shown inFig. 5 after it has been through the process of folding the sheet metalalong its longitudinal axis and the subsequent process of bending itintothe curved or crescent form which it has in the completed caliper, butbefore the outer edges have been brought together and brazed. Fig. 7 isan edge view of the portion of the frame in the same state ofmanufacture made from the blank shown in Fig. 5, which portion of theframe is shown in elevation in Fig. 6.

In the drawings, 2 represents the chief or body portion of thecaliper-frame. This frame is constructed of sheetsteel, is hollow fromend to end, is light in weight, and is strong and rigid in quality. Ateach end this body portion of the frame is provided with leg terminalsor boxes 3. These boxes are of metal and are substantially solid, beingeach provided with a tang i, that [its into the hollow of the leg of thebodyQof the frame at the end thereof and is secured therein by a rivet5, advisably brazed in place. At the inner end of the tang 4 there is ashoulder 6, against which the end of the leg of the body of the framefits and. rests. The box 3 at the left in Fig. 1 is bored in thedirection of the length of the caliper to receive snugly but adjustablytherein the spindle 7. The box 3 at the right in Fig. 1 is bored in thedirection of the length of the caliper to receive snugly but adjustablytherein the sleeve 8, which receives and holds adjustably therethroughthe spindle 9. Both of these boxes are bored at a sheet steel.

right angle, respectively, to the spindle 7 and to the sleeve 8 toreceive therein a spindle and a sleeve-clamping device. The bore for theclamping device intersects near one side the bore for the spindle andfor the sleeve. The clamping device may consist of a screw 10, providedwith a head 11,that fits snugly but movably in the clamping-device borein the box and bears at its inner end, by means of a suitably-facedsurface of the inner end of the head 11, against the spindle or thesleeve. A collar 12, loose on the screw 10, also fits in the bore of thebox opposite and complementary to the head 11 on the screw and bears, bya suitably-faced portion thereof, against the spindle 7 or the sleeve 8.A thumb-nut 13, turning on the screw 10, bears against the collar 12,and by a turning down of the nut the collar 12 and the head 11 resistingoppositely against the box are made to clamp on the spindle 7 or sleeve8 and to clamp them firmly in place in the box. A nut 14, turning byscrew-thread on the exterior of the sleeve 8 against the end of the box4, is adapted to pull, and thereby adjust, the sleeve 8 endwise inwardlyin the box, in which it fits snugly but movably.

The spindle 9 is provided on its outer end with a micrometer 15, whichis a means in common use for adjusting a spindle of this character withgreat exactness; but which micrometer forms no part of my invention, anda further description of it is not here re- 'quired.

In initially adjusting the sleeve 8 in place in the box 1, the nut 14:being removed from the sleeve, the sleeve is inserted in the bore in thebox, but as it fits snugly therein is pushed toward its seat onlyapproximately, and the nut 14 is then put on the sleeve and turned downagainst the box to such extent as is necessary to draw the sleeve 8 intothe box to the place desired, and thereupon the sleeve is clamped inplace by the clamping device.

The body 2 of the frame of the caliper is, as has hereinbefore beenstated, constructed of For this purpose a blank A is cut fromsheet-steel in the form shown in Fig. 5, and this blank is then foldedalong its longitudinal axis, the fold being of a semicircular form, asindicated in Fig. 7 and in Fig. 2, thereby bringing the leaves of theblank thus formed opposite and parallel to each other at a distanceapart. Thereupon this straight but folded blank is bent, and therebycurved, into the form longitudinally shown in Figs. 6 and 7, andthereafter the outer edges of the thus-formed structure are broughttogether along a medial exterior line and are brazed to each otherthroughout the entire length of the frame in the manner best shown inFig. 2, thus forming the completed body of the frame. (Shown in Fig. 1.)This body of the frame is of crescent form, being constructed ofsheet-steel and being wider transversely at its middle portion than itis at the end or leg portions is, notwithstanding it is hollow, verystrong. The form and character of the structure is such as to give ittruss'like strength. The middle and medial portions of the frame beingwider than the terminal portions gives it strength in the medial portiontransversely, especially in radial direction from the axis of thespindles. The frame is thus made absolutely rigid against any yieldingor bending or vibration that would otherwise permit of the end movementor lateral movement of the spindles even to the slightest extent, andwith all the frame is very light, so that the implement can be easilyand readily handled with absolute reliance on its rigidity, even thoughof large size. It will be understood that because of the greaterwidth ofthe body of the frame medially the frame is made strong in andthroughout the medial portion thereof, where strength against collapsingor vibrating is required, while since the frame diminishes in sizetoward the ends of the legs where less strength in transverse directionis sufiicient not only great and sufficient strength is obtained in theframe, but also the minimum of lightness, and thereby capability ofbeing easily manipulated is also secured.

hat I claim as my invention is 1. A caliper, comprising acrescent-shaped hollow frame, solid boxes fitted and secured to the legsof the frame, and spindles adjustable endwise in the boxes in thedirection of the length of the caliper.

2. In a caliper, a metal hollow crescentshaped frame of greatertransverse width medially than at its ends, spindle-boxes at the ends ofthe frame in axial alinement with each other, and spindles adjustableendwise in the boxes.

3. A caliper-frame, formed of asingle piece of sheet-steel initially ofelongated and medially-widened form folded centrally longitudinally andbent into arched shape along and about its folded line, its outer edgesbeing brought together and brazed to each other forming a flattenedoblong structure in crosssection, wider radially medially than near andat its ends.

4. A caliper-frame formed of a single piece of sheet-steel folded andbent along its central longitudinal line into widened hollow form incross-section and bent into arched form along its length and brazedtogether along its outer edge being hollow in its complete structureflattened radially and of maximum strength and minimum lightness.

5. In a caliper, a hollow crescent-shaped frame of sheet-steel the sheetbeing folded centrally longitudinally and bent along and about its innercentral longitudinal line, and spindle-holding boxes fitted into andsecured in the hollow ends of the sheet-steel frame.

6. In a caliper, a frame, a spindle-box in the frame the box being boredtransversely in one direction for the spindle and being boredtransversely at a right angle to the spindlebore for a clamping device,the clamping-device bore intersecting the spindle-bore, a cylindricalspindle in the spindle-bore, and a clamping device loose and movableendwise in the clamping-device bore, the clamping device consisting of ascrew with a head fitting and movable endwise Without revolution in theclamping-device bore, a collar on the screw complementary to the head ofthe screw also fitted and movable end Wise without revolution in theclamping-device bore, the head on the screw and the collar being adaptedto bear opposite each other against the spindle and when drawn towardeach other to force the spindle against the opposite wall of the spin-FRANK M. DAVIS.

Nitnesses:

(J. T. BENEDICT, ANNA F. SOIIIMIDIITBAUER.

